The invention concerns a drive device for adjusting the mirror assembly of a rear-view mirror for a vehicle according to the introductory part of the main claim.
A rear-view mirror comprises in a known manner a mirror base which is attached to a vehicle and a mirror head consisting of a mirror head housing and a mirror glass assembly held in the housing and an adjusting drive connected to the mirror glass assembly. The adjusting drive usually has two electric motors, a horizontal motor and a vertical motor, which pivot the mirror glass assembly by means of an associated mechanism about a horizontal axis and a vertical axis. Adjustment of the mirror assembly is controlled by means of an operating switch which is arranged in the interior of the vehicle and can be operated by the driver or front-seat passenger. In this case the operating switch usually can be operated in four directions, wherein, depending on the direction of operation, different motor signals which steer the respective vertical or horizontal motor in one or the other direction are delivered. Usually the electrical connection between the operating switch and the adjusting drive consists of three wires, wherein one wire is connected both to the vertical motor and to the horizontal motor and the other two wires are connected to the horizontal motor or to the vertical motor respectively.
For larger vehicles or trailers, there are used rear-view mirrors in which the mirror head can be rotated about a pivot point for example from a horizontal position to a vertical position, so that in certain situations what is happening around the vehicle and behind the vehicle can be observed better. As the adjusting drive which is in the mirror housing is rotated with the mirror head, there is no longer coordination between vertical and horizontal adjustments of the operating switch and vertical and horizontal adjustments of the mirror glass or mirror glass assembly.
It is therefore the object of the invention to provide a drive device for adjusting the mirror assembly of a rear-view mirror, which even on rotation of the mirror head in relation to the mirror base out of a first position, for example a horizontal position, into a second position, for example a vertical position, retains the coordination between the respective direction of adjustment delivered by the operating switch and the direction of adjustment of the mirror glass.
This object is achieved according to the invention by the characterising features of the main claim in conjunction with the features of the introductory part.
Due to the fact that the drive device has an electrical/electronic switch-over device which includes a position switch, wherein the position switch occupies different switching states depending on the first and second positions, and that the switch-over device switches the signals delivered to the electric motor assembly as a function of the switching state of the position switch in such a way that both in the first and in the second position of the mirror head the coordination between the direction of locking predetermined by the operating switch and the direction of adjustment of the mirror assembly is maintained, it is possible to move the mirror head into different positions to improve the capacity for recognition of the situation behind and beside the vehicle, without the user having to alter his habits with respect to the setting of the mirror assembly of the mirror head.
Due to the measures provided in the subsidiary claims, advantageous developments and improvements are possible.
It is particularly advantageous that with two electric motors, a horizontal motor and a vertical motor, and with a voltage supply via three wires, the motors being connected to a common wire and to the respectively remaining separate wires, there are provided two relays via whose contacts, depending on operation of the operating switch and on the switching state of the position switch, the horizontal motor is used sometimes for horizontal adjustment and sometimes for vertical adjustment and in a corresponding manner the vertical motor is used sometimes for vertical adjustment and sometimes for horizontal adjustment. At the same time the contacts of one of the relays carry out a necessary reversal of the direction of rotation of at least one of the motors.
Furthermore, in an advantageous manner the voltage supply of the switch-over device is obtained from the respective adjustment signals for the motors, wherein the relays are supplied via an OR link of the signals for horizontal or vertical adjustment, which link is made by diodes, advantageously of a rectifier bridge. By connecting the diodes or linking each to a transistor, interlocking of the motor signals is formed to avoid an inductive disturbance to the other one.
For the position switch which detects the position of the mirror head and in one of the positions closes a circuit of the switch-over device, any switches can be used, for example mechanical, electrooptical, inductive, capacitive, magnetic switches or a combination thereof.